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_47387 ( "Poll Source" text, "Dates administered" text, "Democrat: Brian Schweitzer" text, "Republican: Roy Brown" text, "Libertarian: Stan Jones" text, "Lead Margin" real )

### Question ###
What is the largest lead margin when Schweitzer has 55% and Jones is not an option?

### Accurate SQL ###

SELECT MAX("Lead Margin") FROM table_47387 WHERE "Democrat: Brian Schweitzer" = '55%' AND "Libertarian: Stan Jones" = 'not an option'