I've been trying to serialize the results of a SOQL query into JSON. But I've run into a problem because one of the items in the SOQL result set is generated by a function rather than a field. And I'm having trouble mapping the non-field into the JSON.

Here's what I'm doing:

String q = 'SELECT Physical_Address_City__c, Contact_Person__c, DISTANCE(Geolocation__c, GEOLOCATION(:lat, :lng), \'mi\') FROM Location__c;
List<Location__c> locationList = Database.query(q);
List<Location> locationRecords = new List<Location>();
 for(Location__c loc : locationList) {
            locationRecords.add(new Location(loc));
}
String locationJSON = JSON.serialize(locationRecords);

RestContext.response.addHeader('Content-Type', 'application/json');
RestContext.response.responseBody = Blob.valueOf(locationJSON);

Public class Location {
	    
        public String City;
        public Strong ContactPerson;
        public Decimal Distance;

	    Public Location(Location__c loc) {
	        this.City = loc.Physical_Address_City__c;
            this.ContactPerson = loc.Contact_Person__c;
            this.Distance = loc.expr0;
	    }
}

But I'm getting the following error:
Error: Compile Error: Invalid field expr0 for SObject Location__c at line 22 column 33

I also tried aliasing the Distance results to DISTANCE in my SELECT statement and reference DISTANCE

this.Distance = loc.DISTANCE;

The mapping is expecting a field, but I'm passing it the results of a function. Any recommendations for how to work around this?

Thank you!