CREATE TABLE table_name_2 (date VARCHAR, edition VARCHAR, opponent VARCHAR)

When was the 1991 world group I with the opponent of Li Fang?
SELECT date FROM table_name_2 WHERE edition = "1991 world group i" AND opponent = "li fang"
SELECT "date" FROM "table_name_2" WHERE "1991 world group i" = "edition" AND "li fang" = "opponent"