CREATE TABLE table_name_13 (s_motor_ship___s_naval_trawler VARCHAR2, grand_total VARCHAR2)

How many ships for the nation with grand total of 20?
SELECT s_motor_ship___s_naval_trawler FROM table_name_13 WHERE grand_total = 20
SELECT "s_motor_ship___s_naval_trawler" FROM "table_name_13" WHERE "grand_total" = 20