CREATE TABLE table_19754 ("Result" TEXT, "Date" TEXT, "Race" TEXT, "Venue" TEXT, "Group" TEXT, "Distance" TEXT, "Weight  ( kg ) " TEXT, "Jockey" TEXT, "Winner/2nd" TEXT)

How many venues were used on 10 Mar 2007?
SELECT "Venue" FROM table_19754 WHERE "Date" = '10 Mar 2007'
SELECT "Venue" FROM "table_19754" WHERE "Date" = '10 Mar 2007'