Change:
    my $out = $Ora_code =~ /ORA\-\d{5}/
to:
    my ($out) = $Ora_code =~ /(ORA\-\d{5})/
.

Adding the first set of parens causes $out to be treated as a one-element list. Without those parens, you have scalar context instead of list context; regex matches in scalar context return "truth" of the match instead of anything captured in the match. That Truth is represented as the "1" you are seeing.

Adding the second set of parens declares what data should be captured when the regex is evaluated during the match.