Conversation so far:
what took place in London?
On July 28, 2012, Phelps placed eighth in the morning prelims for the 400-meter individual medley.
what did he place after that?
Phelps, the two-time defending Olympic champion, won his heat in 4 minutes.
was this a record breaking time?
13.33 seconds with a time that was well off his world record of 4:03.84 set four years ago in Beijing, when Phelps won a record eight gold medals.
who were other competitors in this competition?
He out-touched Laszlo Cseh by 0.07 seconds in his heat to qualify last for the final.
was this competition at the olympics?
In his first finals of the Summer Olympics.
what other events did he participate in during this Olympics?
The next night, in his second event of the Games, he got a silver as a member of the 4x100-meter free relay.
who took gold in that relay?
CANNOTANSWER.
was he in any other events?
On July 31, 2012, Phelps won a silver medal in the 200-meter butterfly.

Question: is there any mention of who he competed against in that?
Self-contained rewrite: Is there any mention of who Michael Phelps competed against in the 200-meter butterfly?