CREATE TABLE mission (mission_id DECIMAL, ship_id DECIMAL, code TEXT, launched_year DECIMAL, location TEXT, speed_knots DECIMAL, fate TEXT)
CREATE TABLE ship (ship_id DECIMAL, name TEXT, type TEXT, nationality TEXT, tonnage DECIMAL)

Please show the most common type of ships.
SELECT type FROM ship GROUP BY type ORDER BY COUNT(*) DESC LIMIT 1
SELECT "type" FROM "ship" GROUP BY "type" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1