Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_22673872_1 (rnd INTEGER, winning_driver VARCHAR, track VARCHAR)

### Question ###
In what round did Al Unser win at Wisconsin State Fair Park Speedway? 

### Accurate SQL ###

SELECT MIN(rnd) FROM table_22673872_1 WHERE winning_driver = "Al Unser" AND track = "Wisconsin State Fair Park Speedway"