CREATE TABLE table_22673956_1 (rnd NUMBER, race_name VARCHAR2)

Daily Empress Indy Silverstone took place on which round?
SELECT MAX(rnd) FROM table_22673956_1 WHERE race_name = "Daily Empress Indy Silverstone"
SELECT MAX("rnd") FROM "table_22673956_1" WHERE "Daily Empress Indy Silverstone" = "race_name"