In all cases where, before the effective date of this Act, an election was held in any school district on the question of increasing any tax rate limit of such district and a majority of the votes cast on such question were in favor of such increase, and the election was otherwise held in substantial compliance with the law then applicable to such elections, such election is declared to be legal and valid for all purposes despite the fact that the ballots used at such election used the words “For” and “Against” instead of “Yes” and “No”.