using ordinal_position

I'm attempting to retrieve data using a select statement without knowing 
the column names. I know the ordinal position but not the name of the 
column (happens to be a date::text and I have 13 fields).

Below provides the name of the column in position 3:

select column_name from (select column_name::text, ordinal_position from 
information_schema.columns where
table_name='wk_test') as foo where ordinal_position = 3;

But how can I use the above as a column name in a normal select statement.

Unlike other databases I just can't use ordinal position in the select 
statement - RIGHT???

Johnf