Who would win in a fight between Jack the drought (based on what we've seen of him) and Pica? I thought of this because the two seem to have a similar type of power in that they both use size to destroy everything.
That being said, the destructive power displayed by pica on dressrosa seemed to be greater than the power displayed by Jack on zou. Obviously that definitely isn't representative of jacks true power, but when I posed the question I sort of had those two things in mind (zou vs. dressrosa)
Jack if everything went well because he crushes and Pica being a swordsman penetrates and lacerates. Also since Pica is essentially rubble, concrete, stone and etc it makes more since. Another note would be that Zoro beat Pica and I don't think Zoro is at the level that he could beat Jack so that would make it a bit more valid.