CREATE TABLE table_2860 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT)

Name the least number for production code for 3abc21
SELECT MIN("No. in series") FROM table_2860 WHERE "Production code" = '3ABC21'
SELECT MIN("No. in series") FROM "table_2860" WHERE "Production code" = '3ABC21'