data import: 12-hour time w/o AM/PM

I am importing data in CSV format. My technique is to COPY the data
into interim tables (starting with a "z") where I analyze them, clean
up inconsistencies; eventually I will populate the "proper" tables with
these data. (In the example below: COPY CSV into zevent, from there
populate event.)

The time field of the event data is givng me a headache: it's in 12h
format but without the AM/PM qualifier!

CREATE TABLE zevent
(
id integer,
previous integer,
"next" integer,
location_id integer NOT NULL,
datum date NOT NULL,
otime character varying(5) NOT NULL
)

CREATE TABLE event
(
id integer NOT NULL,
location_fk integer NOT NULL,
otime timestamp without time zone NOT NULL,
next_fk integer,
previous_fk integer,
CONSTRAINT event_pkey PRIMARY KEY (id),
CONSTRAINT next_event_fk FOREIGN KEY (next_fk)
REFERENCES event (id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION,
CONSTRAINT previous_event_fk FOREIGN KEY (previous_fk)
REFERENCES event (id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION
)

From the date and time I want to create a timestamp.
I know that
- the events take place during the day, say between 10:30 and 22:30
- it's always a set of events at one location spaced about 30min apart
- the imported data are chained (have a link to previous/next event)

Have you got any idea how I could tackle this problem

--

Best Regards,
Tarlika Elisabeth Schmitz