CREATE TABLE table_204_853 (id DECIMAL, "pos" DECIMAL, "grid" DECIMAL, "no." DECIMAL, "driver" TEXT, "team" TEXT, "manufacturer" TEXT, "laps" DECIMAL, "points" DECIMAL)

which driver placed highest for roush racing ?
SELECT "driver" FROM table_204_853 WHERE "team" = 'roush racing' ORDER BY "pos" LIMIT 1
SELECT "driver" FROM "table_204_853" WHERE "team" = 'roush racing' ORDER BY "pos" NULLS FIRST LIMIT 1