I get the funny feeling your 'first column' is just a string like this "(a, b, c, d)"
(but I might be wrong, as I am new at this)
If that is the case, removing the parentheses and then splitting on the comma will fix your issue:
my $set = $res;
#I use a lot of 'extra' variables to tell me what everything is
$set =~ s/[\(\)]//g;
#remove all parentheses
my @values = split(',', $set);
#now every value should have its own spot in the array
I hope this solves your problem.
Please ignore me if this is a stupid answer...