CREATE TABLE table_name_99 (geohash_length INTEGER, lat_error VARCHAR(255), lat_bits VARCHAR(255))
What is the highest geohash length when the lat error is ±0.00068, and the lat bits larger than 17?
    
SQL: SELECT MAX(geohash_length) FROM table_name_99 WHERE lat_error = "±0.00068" AND lat_bits > 17