CREATE TABLE table_16273 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "U.S. viewers  ( millions ) " CLOB)

What's the date of the first airing of the episode with series number 63?
SELECT "Original air date" FROM table_16273 WHERE "No. in series" = '63'
SELECT "Original air date" FROM "table_16273" WHERE "No. in series" = '63'