The last election was in 2005. Future elections have been "postponed indefinitely" by current president Mahmoud Abbas.
https://en.wikipedia.org/wiki/Next_Palestinian_presidential_election
Must be recognized internationally as a valid and fair election for the leadership of the State of Palestine (particularly by the UN and leaders of western nations).
Doesn't necessarily need to be called a "presidential election".
Disqualifying some potential candidates (Like Hamas) is ok.
I will not be betting on this market.
This market will be resolved according to the spirit of the question if there is ambiguity.
Related questions
There was also an election in 1996. (The 1996 and 2005 elections seem to have been the only two elections in Palestine since its current gov't was founded in 1994.)