LOS ANGELES (AP) _ Lance Ito, the newly appointed trial judge in the O.J. Simpson case, made his national television debut Monday displaying firm control, a wry wit and the confidence to reverse direction when necessary.

When Deputy District Attorney Marcia Clark was late returning from a 15- minute break - she was the last attorney to take her place at the counsel tables - Ito sat in silence until she arrived.

''When I say 15 minutes, I mean 15 minutes,'' he cautioned at the next recess.

As scientific references to DNA testing became more and more technical, the judge confessed: ''I have no idea what you're talking about,'' adding he might be a little out of his league since the science he majored in at the University of California, Los Angeles was political science.

More revealing, Ito, who was appointed trial judge at a hearing last Friday, wasn't afraid to change his mind.

When Clark protested that the judge's plan to split blood samples between the prosecution and defense was ''taking evidence out of our hands forever,'' Ito changed his mind and said he would wait for expert testimony at a later hearing.

''That was certainly a patient demonstration. He allowed a lot of back and forth,'' said Stanley Goldman, a law professor at Loyola University in Los Angeles. ''Here's a judge who's not embarrassed on national TV to make a ruling and then go back on it.''

At one point, Ito referred to his dilemma over splitting the blood samples as, ''A Yossarian situation.''

The judge added, ''You know, ''Catch 22,'' a Joseph Heller novel whose protagonist, Yossarian, is an Air Force captain who doesn't want to fly bombing missions yet is trapped by a rule known as Catch 22.