Arbitrary powerlevel wise it should be Luffy>Zoro, in a fight Zoro should win on paper since, even if Luffy is meant to be stronger, Zoro has an advantage in match up which should more than bridge that difference, but on paper that happens to be this manga even considering that advantage Luffy would still win.
TLDR: Zoro could win in Death Battle but Luffy would win in One Piece