I don't know. All have their strengths
Jiraiya has SM
Oro is Oro
Tsunade has the best summoning and 100 healings.
:|:|:|I see them pretty much as equals, although it seems that Tsunade has the upper hand against the other two.
Jiraiya's SM was not so impressive. I would put him last. Assuming the fact that a fight would ensue and take orochimaru unprepared to gather his DNA samples for Edo Tensei, he would fall before Tsunade, not without putting up a god fight though.1. Orochimaru - Zetsu body, immortality, Edo Tensei
2. Jiraiya - Sage Mode
3. Tsunade - ...