I would say Sarutobi+Jiraiya, but it is indeed a hard choice.
Deidara is extremely strong, he had some amazing jutsus (like the last one, where he killed himself) and a very powerful/skilled shinobi with an unique trait (or so it seems).
Orochimaru, we all know how strong he is already. He's clever and powerful.
Now, my reasons of why Jiraiya and Sarutobi would win:
During the Orochimaru vs Sarutobi fight, Sarutobi was defeated but he was very close to finish Orochimaru, that's why, with Jiraiya by his side Orochimaru would be defeated. Now, Deidara is also in the game, so the difficulty is greater.
Still, Deidara was killed by Sasuke (i know he killed himself, but in a try of taking Sasuke with him). Jiraiya was way stronger than Sasuke at that moment, and so Deidara wouldn't be able to fight one of the Sannin and win.
So yeah, IMO Sarutobi+Jiraiya > Oro+Deidara
