D-D-D-D-D-DISNEY DUEL! Villains edition! Two antagonistic sorcerers who are commonly seen as some of Disney's most iconic villains. They both transform into mythical creatures in the climax of their fights (a genie for Jafar and a dragon for Maleficent), and they both have beef with the royal figures of their films, Jafar simply wanting to overthrow the sultan, and Maleficent having... no real reason for hating the king unless you take that crappy live-action movie into account.
All right, if this were to be an episode of UniVS, then the way I see it happening, it would just be their debut movies that are taken into account. No sequels or reboots and no Kingdom Hearts, and both would be allowed all of their transformation, being the snake and genie for Jafar and the dragon for Maleficent, with the genies can't kill people rule being removed for the sake of debating. At least, that's how I like it. In this case, I would say Jafar would take it. While we don't see much of Jafar's genie form in the movie, we can see in Return of Jafar he does have reality-warping powers just like everyone's favorite Genie, which would be a safe assumption even if Return of Jafar isn't taken into account. Plus the only time we've really seen Maleficent fight anyone directly is in her dragon form against the prince. Other times she had her goons jump him or just fought him by casting a couple of spells to slightly inconvenience him. And I doubt a dragon would be able to do much against Jafar's genie form.