This must be hypothetical because there is no DH for real baseball-NL.
You state that pitching is equal. On paper, sure, but it doesn't translate that way when games are played. As the saying goes, "momentum is only as good as tomorrow's starting pitcher".
In your scenario, most everything being equal, defense would probably win in seven games.
One of the beautiful aspects of sport is that it is all live, and anything can happen.


Let's say there's an American League team and a National League team that have equally good pitching. Let's say the senior league is loaded with home run hitters. They have a DH specifically for this. Their weakness is that they strike out a lot.
Let us further assert that the National League team has a true lead off hitter, guys who know how to get on base, bunt and steal. Their weakness is that they have only one or two guys who have hit one out of the park since Little League. Who wins a 7 game series? And for all you smart asses out there, let me beat you to the punch: it sure won't be the Cubs!