use Data::Dumper;
my %hash;
my @n = map { /(Character|ASCII)\s*?=\s*?(\S+)/; $1 ? [$1,$2] : () } <DATA>;
while (my ($a, $b) = splice @n, 0, 2) {
        if ($a->[0] eq 'ASCII') {
                $hash{$b->[1]} = $a->[1];
        } else {
                $hash{$a->[1]} = $b->[1];
        }
}
print Dumper(\%hash);

__DATA__
--------------------
ASCII=1
Character=2
Decimal=970
Hexidecimal=3CA
Entity name=
Decription=i with an umlaut
--------------------
Character=4
ASCII=3
Decimal=39
Hexidecimal=27
Entity name=
Decription=quote
---------------------
ASCII=<
Character=<
Decimal=60
Hexidecimal=3C
Entity name=lt
Decription=less than