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_21793 ( "Poll Source" text, "Dates administered" text, "Democrat: Jay Nixon" text, "Republican: Kenny Hulshof" text, "Lead Margin" text )

### Question ###
Who's the poll source that claimed the Lead Margin was 17 and the Democrat: Jay Nixon had 54% of the votes?

### Accurate SQL ###

SELECT "Poll Source" FROM table_21793 WHERE "Democrat: Jay Nixon" = '54%' AND "Lead Margin" = '17'