I hope you mean the very last digit of a line, not the last digit of '-' pattern.

#! /usr/bin/perl
use warnings ;
use strict;
open(FH,"infile") or die "File cant be opened\n";
while (<FH>)
{
        if (m/\d-(\d)"$/)
        {
                print "$1\n";
        }
}
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Infile

"1-2, 3-4, 5-6"
or
"1%5, 3-4"
or
"1-2"
A6
12
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