If we assume it's in JAPAN, then Oda. But if not then probably Emiya, though Oda is still very powerful servant

But would Nobunaga be able to affect EMIYA? Nobunaga's Noble Phantasm is specialized for battles against Divine Servants, which EMIYA is not. And since EMIYA is a modern Servant, Nobunaga's skill also shouldn't work to a significant extent.

Oh right, kinda forgot about that part