Table schema:
CREATE TABLE table_name_90 (react INTEGER, rank VARCHAR, nationality VARCHAR, lane VARCHAR, time VARCHAR)

Question: What's the smallest react of Zimbabwe, ranked after 1 in a lane after 3 and a time less than 20.3?
SQL: SELECT MIN(react) FROM table_name_90 WHERE lane > 3 AND time < 20.3 AND nationality = "zimbabwe" AND rank > 1