CREATE TABLE table_13539 ("Class" TEXT, "Wheel arrangement" TEXT, "Fleet number ( s ) " TEXT, "Manufacturer" TEXT, "Year made" TEXT, "Quantity made" TEXT, "Quantity preserved" TEXT)

What is the Quantity made when class is f-7?
SELECT "Quantity made" FROM table_13539 WHERE "Class" = 'f-7'
SELECT "Quantity made" FROM "table_13539" WHERE "Class" = 'f-7'