Table schema:
CREATE TABLE table_name_21 (total INTEGER, snatch VARCHAR, event VARCHAR, clean_ VARCHAR, _jerk VARCHAR)

Question: What is the lowest total that had less than 170 snatches, 56 kg events and less than 145 clean & jerk?
SQL: SELECT MIN(total) FROM table_name_21 WHERE snatch < 170 AND event = "56 kg" AND clean_ & _jerk < 145