CREATE TABLE table_204_384 (id DECIMAL, "#" DECIMAL, "air date" TEXT, "timeslot  ( est ) " TEXT, "season" TEXT, "rating" DECIMAL, "share" DECIMAL, "18-49  ( rating/share ) " TEXT, "viewers  ( m ) " DECIMAL, "weekly rank  ( # ) " DECIMAL)

which air date had the least viewers ?
SELECT "air date" FROM table_204_384 ORDER BY "viewers (m)" LIMIT 1
SELECT "air date" FROM "table_204_384" ORDER BY "viewers (m)" NULLS FIRST LIMIT 1