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_1971074_1 ( joined VARCHAR, location VARCHAR )

### Question ###
In how many different years did schools located in Logan Township, Pennsylvania join the Conference?

### Accurate SQL ###

SELECT COUNT(joined) FROM table_1971074_1 WHERE location = "Logan Township, Pennsylvania"