Al Unser ชนะที่สนามแข่งรถ Wisconsin State Fair Park ในรอบใด?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
In what round did Al Unser win at Wisconsin State Fair Park Speedway?It is not neccessary to use all the tables.
 table_22673872_1:  (rnd [ INTEGER ] winning_driver [ VARCHAR ] track [ VARCHAR) ]
SELECT MIN(rnd) FROM table_22673872_1 WHERE winning_driver = "Al Unser" AND track = "Wisconsin State Fair Park Speedway"