You shouldn’t count on oxygen from your houseplants to keep you breathing when there’s no other source of oxygen available.
Yes, they do produce a surplus of oxygen over carbon dioxide, but … not much. There are all sorts of complications in calculating this, but a few sources suggest the average leaf gives off about 5 milliliters of oxygen per hour (although that amount varies according to whether the plant is actively growing or not).
People, however, need 23 liters (that’s 23 thousand milliliters!) per hour.
If you were sealed in a room with no other source of oxygen, it would take about 150 to 300 fairly leafy, lustily growing plants to produce the oxygen you’d need to stay alive.
As a result of this calculation, I suggest avoiding sealed rooms if at all possible!