Just one more line for @tofutim answer ... if you want custom field name for concatenated row ...
SELECT
(
col1 || '-' || SUBSTR('00' || col2, -2, 2) | '-' || SUBSTR('0000' || col3, -4, 4)
) AS my_column
FROM
mytable;
Tested on SQLite 3.8.8.3, Thanks!