Table schema:
CREATE TABLE table_13663434_1 (na__350_ VARCHAR, title_and_source VARCHAR)

Question:  how many na -350- with title and source being bokumo sekai wo sukuitai: battle tournament
SQL: SELECT COUNT(na__350_) FROM table_13663434_1 WHERE title_and_source = "Bokumo Sekai wo Sukuitai: Battle Tournament"