Trying to figure out who would've won between the two in the Tsunade arc, but I feel like Jiraiya being drugged and Orochimaru not having his hands makes everything kinda pointless.
So new scenario:
We're in the middle of the Invasion of Konoha from the Sand and Sound. Orochimaru managed to kill the Third without losing the use of his arms, but lost his two Edo Tensei. The barrier dissipates, and the Sound Four are attacked by Kakashi and the rest of the Jonin.
Orochimaru prepares to step in, that's when Jiraiya lands on top of that roof. He sees Hiruzen's dead body. And glares at Orochimaru.
I wanna say Jiraiya, because of SM, but Orochimaru's got the Third Kazekage as an Edotensei, by this time...
In reality I don't think it was ever specified when Jiraiya actually learned Sage Mode. DB4 and the manga are the only real sources on it and I don't think they specified. So it is entirely possible Jiraiya learned his Sage Mode in the 3 years between P1 and P2, with the Akatsuki threat and Naruto's safety at hand more than ever it would make sense for him to finally decide to learn it for himself.
It showed him training with it as a kid, it didn't show him successfully using it in combat. Since he never mastered it, he may have excluded it from his repertoire until the increasing threat of the Akatsuki forced him to train to use it in battle.
In any case, I said if we go by abilities shown in Part 1. Keyword is shown. Because it's hard to speculate when we give Part 2 abilities to Part 1 characters. For example, Kakashi unlocked his Mangekyo when he was around 14. Yet he fought many difficult opponents and his Hokage even died without him ever showing the technique in Part 1. So usually if we say Part 1 Kakashi, we exclude Kamui, despite knowing he unlocked it.