The following CREATE TABLE statement defines a PERIOD(TIMESTAMP(3) WITH TIME ZONE) column with a default value specified using WITH DEFAULT. The WITH DEFAULT option sets the default value to a Period value constructor with the beginning argument set to CURRENT_TIMESTAMP(3) and the ending argument set to UNTIL_CHANGED.
CREATE TABLE t4 ( employee_id INTEGER, employee_name CHARACTER(15), employee_duration PERIOD(TIMESTAMP(3) WITH TIME ZONE) WITH DEFAULT );