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_68742 ( "Region served" text, "City" text, "Channels ( Analog / Digital )" text, "First air date" text, "ERP (Analog/ Digital)" text, "HAAT (Analog/ Digital) 1" text, "Transmitter Location" text )

### Question ###
What channels first aired on 31 December 1990 in the Southern Downs region?

### Accurate SQL ###

SELECT "Channels ( Analog / Digital )" FROM table_68742 WHERE "First air date" = '31 december 1990' AND "Region served" = 'southern downs'