There is no way Jiraiya would lose:
Jiraiya can counter all of Orochimaru's move, he can sink Manda and other snakes easily with his Swamp of the Underworld. His Fire release is awesome and his earth technique surpasses many.
Jiraiya can summon Gamabunta and Gamaken, and many other toads. He can use toad oil bullet, and toad flame bullet and his hair jutsu would protect him from close combat if needed.
Now Jiraiya would get into Sage Mode - which means he got Ma & Pa on his shoulders, the two mighty sages of Mount Myoboku, who has immense knowledge and skill within Sage Art and has a lot of jutsu, including their Genjutsu which would reck Orochimaru.
In Sage Mode, jiraiya would be too fast for Orochimaru, and Jiraiya was so strong he could one hit KO one of Pein's bodies. Also how do you expect Orochimaru to counter: Senpou Goemon - vast sea of boiling oil, also Chou Oodoma Rasengan - epic Rasengan of destruction and his many other techniques within the Toad arts.
Jiraiya can counter Orochimaru's snakes easily, he has no problem with the Hydro mode, since it is a big target so just go Oodoma Rasengan or Goemon on it and it's over, now Orochimaru would need the 2 Edo Tensei, just to be on par with Jiraiya in this battle.
But Jiraiya knows of this tech, and even so, Edo Tensei, the two shinobi would be smashed to pieces easily so that he could continue on Orochimaru.
Jiraiya > Orochimaru - Orochimaru does not know everything about Jiraiya, since he left the village, before he Jiraiya completed all his training in Mount Myoboku and he knows little of his jutsu.
Edo Tensei: any two powerful shinobi, they would not be fast enough to counter Jiraiya SM with his Arsenal. (Especially if we say it would be Hashirama and Tobirama)
Hydro Mode: Wrecked by Jiraiya - Goemon, Oodoma Rasengan
Snakes: Swamp of the underworld
Now the only reason Pein's 3 bodies really had a chance of beating Jiraiya was because of their shared link, or else they would have been dead, in the matter of seconds.
Jiraiya is way above Orochimaru's level.
Jiraiya defeats Orochimaru Mid-High difficulty.