CREATE TABLE table_44510 ("Year" CLOB, "Supplier" CLOB, "Chest" CLOB, "Sleeves" CLOB, "Back" CLOB)

Which Sleeves have a Back of Unknown?
SELECT "Sleeves" FROM table_44510 WHERE "Back" = 'unknown'
SELECT "Sleeves" FROM "table_44510" WHERE "Back" = 'unknown'