Luke Skywalker (ROTJ) vs. Darth Sidious(ROTJ)
Let's use all of our vast EU knowledge about Luke and Palpatine's force powers at the time of ROTJ, to see what would happen in a straight up fight between them. (like suppose vader wasn't there and luke just had to fight palpatine in a duel.)
the ROTJ palpatine had no lightsaber, he just had his force powers
the rotj luke had a combination of his force powers and lightsaber.