How many postal points with unique post office types are there in Ohio?
postal points refer to zip_code; unique post office types refer to type = 'Unique Post Office'; Ohio is the name of the state, in which name = 'Ohio';
SELECT COUNT(T2.zip_code) FROM state AS T1 INNER JOIN zip_data AS T2 ON T1.abbreviation = T2.state WHERE T1.name = 'Ohio' AND T2.type = 'Unique Post Office'