CREATE TABLE table_74446 ("Series #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "France air date" TEXT, "Canadian air date" TEXT, "US air date" TEXT)

What is the series # when the US air date is 20 July 2012?
SELECT MIN("Series #") FROM table_74446 WHERE "US air date" = '20 July 2012'
SELECT MIN("Series #") FROM "table_74446" WHERE "US air date" = '20 July 2012'