Sixth or third, I would guess. Those are the times the Doctor has regenerated to an older looking version.
If I were a betting man, I'd say that the 12th would be of the same ilk as the 6th, who was the same ilk of the 1st.
Note: 11th seems to be of the same ilk as the 2nd, and 8th seems to be the same ilk as the 4th.