easy way to insert same value into 2 columns

Hello,

whats the most simple way to insert the same value into 2 colums of 
the same table?
My table is looking like this:

  Spalte |   Typ   |     Attribute
--------+---------+----------------------
  id     | integer | default nextval ('public.zeit_id_seq'::text)
  pos_id | integer | default xxx

for the xxx i want the same value than id be inserted automatically

Regards

Sebastian