Gov. Mike DeWine has appointed former Gov. Bob Taft’s top aide to the retired teachers’ pension fund. Jon Allison, a Columbus-based attorney, will replace controversial leader Wade Steen.Allison served as the chief of staff for Taft from 2003-2006 after working in state government for years. Most recently, he has been the chief administrative officer for Root Inc., a car insurance company, after serving as their general counsel.