Well, here is what I would start with:

use strict;

 while(<DATA>)
 {
     #using re match.
     # match beginning, anything except comma,
     # followed by a comma and 'Y'
     if(m/^([^,]+),Y/)
     {   
         print "RE Name:" . $1 . "\n";
     }
}


__DATA__
davis,N
brown,Y
smith,Y,N,B
jones,N,Y,B,A
clarke,Y,N,Y
[download]

Or Perhaps:

use strict;

 while(<DATA>)
 {
     my @data = split(',');

     if($data[1] eq 'Y')
     {   
         print "RE Name:" . $data[0] . "\n";
     }
}


__DATA__
davis,N
brown,Y
smith,Y,N,B
jones,N,Y,B,A
clarke,Y,N,Y
[download]