CREATE TABLE table_203_439 (id DECIMAL, "pos." DECIMAL, "rider" TEXT, "semi-final points" DECIMAL, "final points" DECIMAL, "final heats" TEXT, "total points" DECIMAL)

their final points is equal to 15
SELECT "rider" FROM table_203_439 WHERE "final points" = 15
SELECT "rider" FROM "table_203_439" WHERE "final points" = 15