CREATE TABLE table_13731 ("Date" CLOB, "Ship" CLOB, "Nationality" CLOB, "Tonnage" FLOAT, "Fate" CLOB)

What is the date for the ship Afrika, with nationality Great Britain?
SELECT "Date" FROM table_13731 WHERE "Nationality" = 'great britain' AND "Ship" = 'afrika'
SELECT "Date" FROM "table_13731" WHERE "Nationality" = 'great britain' AND "Ship" = 'afrika'