Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Title | Role | Notes |
| --- | --- | --- | --- |
| 1979 | California Fever | Lisa Bannister | Episode: "The Girl from Somewhere" |
| 1984 | Faerie Tale Theatre | Snow White | Episode: "Snow White and the Seven Dwarfs" |
| 1993 | Performance | Beatrice-Joanna | Episode: "The Changeling" |
| 1995 | If Not for You | Jessie Kent | 8 episodes |
| 1996 | Tracey Takes On... | Judge Loring | Episode: "Vanity" |
| 1996 | Tales from the Crypt | Laura Kendall | Episode: "Horror in the Night" |
| 1999 | The Scarlet Pimpernel | Lady Margaret Blakeney | 3 episodes |
| 2001 | Table 12 | Mel | Episode: "Preserves" |
| 2003 | The Brotherhood of Poland, New Hampshire | Helen Shaw | 7 episodes |
| 2006 | Three Moons over Milford | Laura Davis | 8 episodes |
| 2007 | Law and Order: Special Victims Unit | Dr. Faith Sutton | Episode: "Harm" |
| 2007–2008 | Freezing | Elizabeth | 3 episodes |
| 2008 | Agatha Christie: Poirot | Dame Celia Westholme | Episode: "Appointment with Death" |
| 2009 | 10 Minute Tales | The Ex-Wife | Episode: "The Running of the Deer" |
| 2010–present | Downton Abbey | Cora, Countess of Grantham | 29 episodes\nScreen Actors Guild Award for Outstanding Performance by an Ensemble in a Drama Series\nNominated—Golden Globe Award for Best Actress – Miniseries or Television Film\nNominated—Primetime Emmy Award for Outstanding Lead Actress in a Miniseries or a Movie\nNominated—Satellite Award for Best Actress – Miniseries or Television Film |
Question:
which tv show did this actress star in the most episodes?
Answer:
Downton Abbey