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_17 ( road_team VARCHAR, home_team VARCHAR, date VARCHAR )

### Question ###
Which Road team has a Home team of portland, and a Date of may 31?

### Accurate SQL ###

SELECT road_team FROM table_name_17 WHERE home_team = "portland" AND date = "may 31"