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_name_20 (opened INTEGER, venue VARCHAR, established VARCHAR)
### Question:
When is the earliest year opened for huff hall that was established after 1974?
### Answer:
SELECT MIN(opened) FROM table_name_20 WHERE venue = "huff hall" AND established > 1974