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:
| No. in series | No. in season | Title | Directed by | Written by | Original air date | U.S. viewers (millions) |
| --- | --- | --- | --- | --- | --- | --- |
| 10.0 | 1.0 | "A Family Thing" | Mark Tinker | Shonda Rhimes & Marti Noxon | October1,2008 | 8.16 |
| 11.0 | 2.0 | "Equal and Opposite" | Tom Verica | Mike Ostrowski | October8,2008 | 7.40 |
| 12.0 | 3.0 | "Nothing to Talk About" | Helen Shaver | Ayanna A. Floyd | October22,2008 | 7.98 |
| 13.0 | 4.0 | "Past Tense" | Michael Pressman | Craig Turk | October29,2008 | 7.93 |
| 14.0 | 5.0 | "Let It Go" | Michael Zinberg | Lauren Schmidt | November5,2008 | 9.54 |
| 15.0 | 6.0 | "Serving Two Masters" | Joanna Kerns | Emily Halpern | November 19, 2008 | 7.14 |
| 16.0 | 7.0 | "Tempting Faith" | James Frawley | Jon Cowan & Robert L. Rovner | November26,2008 | 6.33 |
| 17.0 | 8.0 | "Crime and Punishment" | Mark Tinker | Shonda Rhimes | December3,2008 | 7.78 |
| 18.0 | 9.0 | "Know When to Fold" | Jeff Melman | Elizabeth J.B. Klaviter | December10,2008 | 6.86 |
| 19.0 | 10.0 | "Worlds Apart" | Bethany Rooney | Steve Blackman | December17,2008 | 6.61 |
| 20.0 | 11.0 | "Contamination" | Kate Woods | Fred Einesman | January8,2009 | 8.98 |
| 21.0 | 12.0 | "Homeward Bound" | Mark Tinker | Sal Calleros | January15,2009 | 8.49 |
| 22.0 | 13.0 | "Nothing to Fear" | Allison Liddi-Brown | Jon Cowan & Robert Rovner | January22,2009 | 9.49 |
| 23.0 | 14.0 | "Second Chances" | James Frawley | Craig Turk | January29,2009 | 7.74 |
| 24.0 | 15.0 | "Acceptance" | Steve Gomer | Mike Ostrowski | February5,2009 | 12.91 |
| 26.0 | 17.0 | "Wait and See" | Michael Zinberg | Steve Blackman | February19,2009 | 11.16 |
| 27.0 | 18.0 | "Finishing" | Donna Deitch | Shonda Rhimes | March12,2009 | 8.80 |
| 28.0 | 19.0 | "What Women Want" | Mark Tinker | Lauren Schmidt | March19,2009 | 9.74 |
| 29.0 | 20.0 | "Do the Right Thing" | Eric Stoltz | Craig Turk | March26,2009 | 10.12 |
| 30.0 | 21.0 | "What You Do For Love" | Tom Verica | Ayanna A. Floyd | April23,2009 | 9.08 |
Question:
What is the number in the series that was titled "Past Tense"?
Answer:
13.0