Tifone:
Your other army sits in a different province. That is tens of miles away! There is no way they can get in time for that battle, no matter how much staling you do
50 turn would be few hours max in real time. So not even realistic approach works here
In late game I had way too many battles ending in turn limit, that was just frustrating [and opponent didn't try to stale, he just put his armies, I put mine and we both tried to win].