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 (year VARCHAR, college VARCHAR, pick VARCHAR, position VARCHAR)
### Question:
How many years have a Pick of 12, and a Position of dt, and a College of penn state?
### Answer:
SELECT COUNT(year) FROM table_name_20 WHERE pick = "12" AND position = "dt" AND college = "penn state"