IMO, no one is harder than any other.
No. 5 = No. 10?No.Regarding the original question, both are quite difficult. Nos. 2, 5, 6 and 11 are considerably easier than either of those; perhaps you should look at them, first. Honestly, if somebody is asking, "which is harder," then they're both too hard, probably. I don't think there is too much between them; No. 3 is probably more difficult at tempo, but No. 12 is much longer and more varied.