CREATE TABLE table_28702 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "U.S. viewers  ( millions ) " TEXT)

What is the highest production code?
SELECT MAX("Production code") FROM table_28702
SELECT MAX("Production code") FROM "table_28702"