User the below mention code as ref

<apex:page id="thePage" standardController="Lead" extensions="SearchAINewLeadController" tabstyle="Lead" standardStylesheets="true" title="Search Duplicates" showHeader="true" sidebar="false" >
 <apex:form id="theForm1">
    <apex:pageBlock id="thePageBlock1" tabStyle="Lead" >
   
   <apex:pageBlockSection id="thePBSection1" collapsible="false"  >
    

            

    
    <apex:pageBlockSectionItem id="thePBSItem3" >
     <apex:outputLabel id="AccountLabel" for="Account" value="Customer Name" />
     <apex:pageBlockSectionItem id="thePBSItem4" >
       <apex:inputtext id="Account" value="{!accopp}"/>
    <apex:outputLabel value="(Aurobindo Pharma)" />
    </apex:pageBlockSectionItem>  
   
    </apex:pageBlockSectionItem>

   </apex:pageBlockSection>
 
   <apex:pageBlockButtons location="bottom">
         <apex:commandButton id="btnSearch" value="Search" onclick="return check();"  />            
              <apex:actionfunction action="{!search}" id="searchaction" name="searchaction" reRender="redpanel" />
   </apex:pageBlockButtons>
  </apex:pageBlock>
 <apex:outputPanel id="redpanel" rendered="{!showLeadList}">
<apex:PageMessages />
 
   <apex:pageBlock title="Lead Details" tabStyle="Lead">
                <apex:pageBlockTable value="{!lstExistingLead}" var="ld" >                
                    
                    <apex:column width="8%">
                        <apex:facet name="header">
                         Name
                        </apex:facet>
                        <apex:outputlink value="/{!ld.Lead__r.id}">{!ld.Lead__r.Name}</apex:outputlink>
                    </apex:column>
                    
                    <apex:column width="16%">
                        <apex:facet name="header" >
                         Customer name
                        </apex:facet>
                        {!ld.Lead__r.Company}
                    </apex:column>
                                   
                   <apex:column width="16%">
                        <apex:facet name="header" >
                         CAS No.
                        </apex:facet>
                        {!ld.Name}
                    </apex:column>  
                    
                    <apex:column width="16%">
                        <apex:facet name="header" >
                         Product Name
                        </apex:facet>
                        {!ld.Product__r.Name}
                    </apex:column>
                    
                    <apex:column width="16%">
                        <apex:facet name="header" >
                         Lead Status
                        </apex:facet>
                        {!ld.Lead__r.Status}
                    </apex:column>
                       <apex:column width="10%">
                        <apex:facet name="header" >
                         Lead Owner
                        </apex:facet>
                        {!ld.Lead__r.Owner.Name}
                    </apex:column>  
               
                </apex:pageBlockTable>
            </apex:pageBlock>
 
  </apex:outputPanel>
 </apex:form>
</apex:page>