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_27440 ( "City" text, "Population" real, "Registered voters" text, "Democratic" text, "Republican" text, "D\u2013R spread" text, "Other" text, "No party preference" text )

### Question ###
What is the d-r spread if the no party preference is 31.8%?

### Accurate SQL ###

SELECT "D\u2013R spread" FROM table_27440 WHERE "No party preference" = '31.8%'