CREATE TABLE table_55204 ("Entrant" CLOB, "Constructor" CLOB, "Chassis" CLOB, "Engine" CLOB, "Tyre" CLOB, "Driver" CLOB, "Rounds" CLOB)

What rounds did Roy Salvadori drive for David Brown Corporation?
SELECT "Rounds" FROM table_55204 WHERE "Entrant" = 'david brown corporation' AND "Driver" = 'roy salvadori'
SELECT "Rounds" FROM "table_55204" WHERE "Driver" = 'roy salvadori' AND "Entrant" = 'david brown corporation'