Don't know if it still holds, but ages ago when I lived in Ohio (more than 30 years ago), they called it 'physical control of a motor vehicle while impaired' if you were in the car with the keys in the ignition (and stewed to the mickey...) whether the car was running or not.
Just in the last 2 years, I read an article where a driver who was sitting in the driver seat until he sobered up was ticketed for a DUI.