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_name_71 (river_mile INTEGER, pool_length__miles_ VARCHAR, lock_lift_drop__in_feet_ VARCHAR)

### Question ###
What is the highest River Mile that has a pool length of 42.2 miles or a lock/lift drop of 21 feet?

### Accurate SQL ###

SELECT MAX(river_mile) FROM table_name_71 WHERE pool_length__miles_ = "42.2" AND lock_lift_drop__in_feet_ = "21"