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_27833186_1 (rider_names VARCHAR, location VARCHAR, horse_name VARCHAR)

### Question ###
Who were the winning riders of the championship in Euer Valley, CA and whose horse was Magic Sirocco?

### Accurate SQL ###

SELECT rider_names FROM table_27833186_1 WHERE location = "Euer Valley, CA" AND horse_name = "Magic Sirocco"