CREATE TABLE table_72137 ("No. in season" FLOAT, "No. in series" FLOAT, "Title" TEXT, "Canadian airdate" TEXT, "US airdate" TEXT, "Production code" FLOAT)

The canadian airdate of 11 february 2008 applied to what series number?
SELECT COUNT("No. in series") FROM table_72137 WHERE "Canadian airdate" = '11 February 2008'
SELECT COUNT("No. in series") FROM "table_72137" WHERE "Canadian airdate" = '11 February 2008'