Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_2970978_1 (ave_attendance INTEGER, ___ave_on_prev_season VARCHAR)
### Question:
What is the least value for average attendance when average on previous season is +644?
### Answer:
SELECT MIN(ave_attendance) FROM table_2970978_1 WHERE ___ave_on_prev_season = "+644"