CREATE TABLE table_203_339 (id DECIMAL, "year" TEXT, "car" DECIMAL, "start" DECIMAL, "qual" DECIMAL, "rank" DECIMAL, "finish" DECIMAL, "laps" DECIMAL, "led" DECIMAL, "retired" TEXT)

what was his best finish before his first win ?
SELECT MIN("finish") FROM table_203_339 WHERE "year" < (SELECT "year" FROM table_203_339 WHERE "finish" = 1 ORDER BY "year" LIMIT 1)
SELECT MIN("finish") FROM "table_203_339" WHERE "year" < (SELECT "year" FROM "table_203_339" WHERE "finish" = 1 ORDER BY "year" NULLS FIRST LIMIT 1)