Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_67 (matches INTEGER, overs VARCHAR, economy_rate VARCHAR)

### Question ###
How many matches were played that resulted in less than 59.1 overs and a 6.78 Economy rate?

### Accurate SQL ###

SELECT SUM(matches) FROM table_name_67 WHERE overs < 59.1 AND economy_rate > 6.78