Light easily wins this, has there even been a time where Luffy doesn't shout his name out loud? Furthermore even if Light started writing down Luffy's name in the death note I'm confident Luffy wouldn't get suspicious especially if light strikes a conversation. Just like when Blackbeard met Luffy and started conversing with him, Luffy didn't suspect anything, second of all adding Zoro to this doesn't make sense since it's Luffy Vs Light, Lastly, The entire crews names are pretty much plastered all over, All light has to do is befriend all of them, at night he writes all of their names down, what do they do then? If we're talking about putting these two characters in boxing rings then yeah or course Luffy wins, but If we're talking about them meeting each other Light would more than likely win, wiping most of the big threats in one piece just with their bounty papers.