Safety pilot "flight time"

When logging safety pilot time, what do you put under the "duration of
flight" column? For example, say I'm flying with a friend who is
wearing a hood. We decided I'll be responsible for the flight before
hand. I can log PIC for the time the other person had the hood on, and
under the "total flight time" column, put the same as the PIC/when he
was wearing the hood?

Someone told me once if the person wore the hood most of the flight,
you could log the "flight time" for the entire flight, because you were
a required crew member. But once he takes it off though, you aren't
required...so I'm thinking it's the same as the PIC time.