Ooooh this is a good one, but I'm going to have to be real here.
Django only killed about... 15-30 guys in the entire movie, that's quite impressive for sure, but it's nothing compared to the 200+ guys that you must kill playing as John Marston in Red Dead Redemption So I'd say John would win.
Yes, and John Marston dies and Django does not, but I still think John would win in a single fight
Beatrix Kiddo from Kill Bill (http://4.bp.blogspot.com/--poSU4By_D8/T8-hJNxET7I/AAAAAAAAAOY/lV8IU4UigcE/s1600/Kill+Bill+1.jpg) or Miho from Sin City (http://images5.fanpop.com/image/photos/31700000/Miho-sin-city-31790492-1024-768.jpg)