CREATE TABLE table_21997 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Country" TEXT, "Project" TEXT, "Status at production" TEXT, "Original air date" TEXT)

What was the original are date of series number 71?
SELECT "Original air date" FROM table_21997 WHERE "No. in series" = '71'
SELECT "Original air date" FROM "table_21997" WHERE "No. in series" = '71'