CREATE TABLE table_21623 ("Series #" FLOAT, "Season #" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB)

What was the number of seasons that was directed by Joanna Kerns?
SELECT COUNT("Season #") FROM table_21623 WHERE "Directed by" = 'Joanna Kerns'
SELECT COUNT("Season #") FROM "table_21623" WHERE "Directed by" = 'Joanna Kerns'