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_26813 ( "Episode no." real, "Airdate" text, "Viewers" real, "BBC Three weekly ranking" text, "Cable rank" text )

### Question ###
What episode number had a cable ranking of 8?

### Accurate SQL ###

SELECT MIN("Episode no.") FROM table_26813 WHERE "Cable rank" = '8'