CREATE TABLE table_21823 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT)

What was the name of eipsode 618?
SELECT "Title" FROM table_21823 WHERE "Production code" = '618'
SELECT "Title" FROM "table_21823" WHERE "Production code" = '618'