Table schema:
CREATE TABLE table_name_13 (total_cargo__metric_tonnes_ INTEGER, code__iata_icao_ VARCHAR, rank VARCHAR)

Question: What is the full amount of Total Cargo (in Metric Tonnes) where the Code (IATA/ICAO) is pvg/zspd, and the rank is less than 3?
SQL: SELECT SUM(total_cargo__metric_tonnes_) FROM table_name_13 WHERE code__iata_icao_ = "pvg/zspd" AND rank < 3