CREATE TABLE table_54390 ("Entrant" TEXT, "Constructor" TEXT, "Chassis" TEXT, "Engine" TEXT, "Tyres" TEXT, "Driver" TEXT, "Rounds" TEXT)

Tell me the constructor for alberto colombo and chassis of a1
SELECT "Constructor" FROM table_54390 WHERE "Driver" = 'alberto colombo' AND "Chassis" = 'a1'
SELECT "Constructor" FROM "table_54390" WHERE "Chassis" = 'a1' AND "Driver" = 'alberto colombo'