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_25229283_4 (points_against INTEGER, opponent VARCHAR)
### Question:
What was the minimum points against if the opponent is Port Adelaide?
### Answer:
SELECT MIN(points_against) FROM table_25229283_4 WHERE opponent = "Port Adelaide"