Columbus zoo and Aquarium has a Dedicated Nursing/pumping building, near the entrance to the Heart of Africa exhibit (very close to the camel rides). It doesn't seem to be clearly marked on their map but it is there! They also say you can use any of the first aid stations. This is as of May 30, 2017.
Some moms call it Nursing Room, Breastfeeding Room, Lactation Station, and others Lactation Room. MomsPumpHere Nursing Room Locator (also Airport Lactation Rooms Locator) is a breastfeeding room finder, nursing room finder, lactation station locator, and lactation room finder. We find moms nice, quiet places to breastfeed or breastpump no matter what they call it. Lactation rooms also help moms relieve oversupply of breast milk which can cause mastitis while breastfeeding.