CREATE TABLE table_203_784 (id DECIMAL, "no. in\ series" DECIMAL, "no. in\ season" DECIMAL, "performer" TEXT, "appearance" TEXT, "air date" TEXT)

which month had the most performers ?
SELECT "air date" FROM table_203_784 GROUP BY "air date" ORDER BY COUNT("performer") DESC LIMIT 1
SELECT "air date" FROM "table_203_784" GROUP BY "air date" ORDER BY COUNT("performer") DESC NULLS LAST LIMIT 1