You could add a '-- ' to $_ and split into two fields, that would give you a blank name, if none exists:

while (<FILE>) {
        chomp;
        $_ .= '-- ';
        my ($quote,$person) = split /--/, $_, 2;
        $quote =~ s/^\s+|\s+$//g;
        $person =~ s/^\s+|\s+$//g;
        print "$quote\t$person\n";
}
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