Among the crew members of the simpson 20s born in the New York city, how many of them were born after the year 1970?
born in New York city refers to birth_region = 'New York'; born after year 1970 refers to ('%Y', birthdate) > 1970
SELECT COUNT(name) FROM Person WHERE birth_region = 'New York' AND SUBSTR(birthdate, 1, 4) > '1970';