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 customer_contact_channels (channel_code VARCHAR, contact_number VARCHAR, active_to_date VARCHAR, active_from_date VARCHAR)

### Question ###
What is the channel code and contact number of the customer contact channel that was active for the longest time?

### Accurate SQL ###

SELECT channel_code, contact_number FROM customer_contact_channels WHERE active_to_date - active_from_date = (SELECT active_to_date - active_from_date FROM customer_contact_channels ORDER BY (active_to_date - active_from_date) DESC LIMIT 1)