ST. MATTHEW
Chapter 10
Apostles Chosen

2. Now the names of the twelve apostles are these; The first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother; 3. Philip, and Bartholomew; Thomas, and Matthew the publican; James, the son of Alphaeus, and Lebbaeus, whose surname was Thaddaeus; 4. Simon the Canaan-ite, and Judas Iscariot, who also betrayed him.

Chapter 26
The Betrayal

17. Now the first day of the feast of unleavened bread, the disciples came to Jesus, saying unto him, Where wilt thou that we prepare for thee to eat the passover? 18. And he said Go into the city to such a man, and say unto him, The Master saith, My time is at hand; I will keep the passover at thy house with my disciples. 19. And the disciples did as Jesus had appointed them; and they made ready the passover. 20. Now the even was come, he sat down with the twelve.

There is no mention in the Bible of anyone else being present at the table, referred to as the Last Supper, except for the disciples.

In reading da Vinci's personal handwritten notes and etchings of words found on his sketches for laying out the painting of the Last Supper, I found absolutely nothing concerning a woman being involved in the painting.  It is something Leonardo would have made a reference to on paper.  He kept written records on what he ate and lists of what he needed to buy to do his work, such as books to read and study, plaster, shoes, if someone died, etc. Surely a man who was meticulous and believed everything should be accounted for, down to the creation of drawing the household fly, in detail, would not leave out the information about a woman being present in the painting of the Last Supper.

Click here to see a painting of Apostle John, and make up your own mind.