CREATE TABLE table_56343 ("Grand Prix" TEXT, "Date" TEXT, "Location" TEXT, "Pole Position" TEXT, "Fastest Lap" TEXT, "Winning Driver" TEXT, "Constructor" TEXT, "Report" TEXT)

What date is the Portuguese Grand Prix?
SELECT "Date" FROM table_56343 WHERE "Grand Prix" = 'portuguese grand prix'
SELECT "Date" FROM "table_56343" WHERE "Grand Prix" = 'portuguese grand prix'