Historical Rules · 18 June 2010
Rule 708.6a
Official source text from the 18 June 2010 Rules release
An effect that performs a positive comparison (such as asking if a card is red) or a relative comparison (such as asking if a card's converted mana cost is less than 2) involving characteristics of one or more split cards in any zone other than the stack gets only one answer. This answer is "yes" if either side of each split card in the comparison would return a "yes" answer if compared individually.