It will need paint, but it takes a while. After about five years the surface can be painted, after about ten years you can start to expect the first small rust dots. At least in our rather humid climate, I dont know much about Ohio, perhaps a rather moderate climate. Painting demands paints that can stand the galvanized surface, but with correct paint and cleaning should be quite straightforward.
I have old fashioned sheet covered roof (if thats the right word) since 2006 on the house and a corrugated galvanized roof on my outbuilding since 2010. No problem so far, but I should pull myself toghether and have the older one painted this summer. When you install a corrugated roof make sure you put screws on top of the ridges to avoid leakage.
