He would have presented the Best Actress award this year, as is usually the tradition: the previous year's Best Actor winner presents the following year's Best Actress. (justjared.com)
No one really remembers who wins best supporting actor, but everyone remembers the best actor winner years later. (incontention.com)
As an example, eight of the last twelve Best Actor winners have won for playing real life people. (theyoungfolks.com)