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_56 (year INTEGER, partnering VARCHAR, championship VARCHAR)

### Question ###
What year was the US Open that had a partnering of Maikel Scheffers?

### Accurate SQL ###

SELECT SUM(year) FROM table_name_56 WHERE partnering = "maikel scheffers" AND championship = "us open"