Only return the values that never occur in subquerry

I've been stuck on this for 3 hours now. I'm sorry for having to ask this here, but I just can't get through it.

I've got a Table with two columns. Column A called "proces" and Column B called "Done". If there is a case where a process isn't done (thus having "0" value in the B column) I don't want to have it return at all.

The subquerry I tried to use is this:

SELECT A 
FROM TABLE
WHERE A NOT IN (SELECT A FROM TABLE WHERE B = 0);

Still, this gives me values I don't want. I really don't understand why this does not work. I basically only want processes to return that only have values of 1 in the B column.