Complex sentence: Ohio's 12th senatorial district has been based in rural western Ohio and currently comprises the counties of Allen, Mercer, Shelby, Champaign as well as portions of Auglaize, Darke and Logan counties.
Split into simpler sentences: Ohio's 12th senatorial district has been based in rural western Ohio. It comprises the counties of Allen, Mercer, Shelby, Champaign as well as portions of Auglaize, Darke and Logan counties.