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_54 (season_joined_league VARCHAR, seasons_at_this_level VARCHAR)

### Question ###
What is the "season joined league" for the club that had 15 seasons at this level?

### Accurate SQL ###

SELECT season_joined_league FROM table_name_54 WHERE seasons_at_this_level = "15 seasons"