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_18 ( total_cargo__metric_tonnes_ INTEGER, code__iata_icao_ VARCHAR, rank VARCHAR )

### Question ###
What is the highest total cargo of an airport ranked larger than 19 with a code of BKK/VTBS?

### Accurate SQL ###

SELECT MAX(total_cargo__metric_tonnes_) FROM table_name_18 WHERE code__iata_icao_ = "bkk/vtbs" AND rank > 19