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

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'