CREATE TABLE table_45280 ("Series Number" FLOAT, "Number of Episodes" FLOAT, "Original Air Date" FLOAT, "DVD Region 2 release date" TEXT, "DVD Region 1 release date" TEXT)

What was the original air date of series number 10?
SELECT AVG("Original Air Date") FROM table_45280 WHERE "Series Number" = '10'
SELECT AVG("Original Air Date") FROM "table_45280" WHERE "Series Number" = '10'