split each line on ; and test if the second element in the list is 3 spaces:

my @interesting = grep { (split /;/)[1] ne '   ' } <DATA>;
print @interesting;
__DATA__
AAD;   ;CCR;365
TEC;UTF;TDE;450
TRE;   ;FTE;164
TEC;URT;TDE;687
ERT;   ;ETR;567
TEC;UGC;TDE;687
[download]

Output:

TEC;UTF;TDE;450
TEC;URT;TDE;687
TEC;UGC;TDE;687
[download]

Not nearly as much fun as your previous question!