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 | Production code |
| --- | --- | --- | --- | --- | --- | --- |
| 27.0 | 1.0 | "Doogenstein" | Eric Laneuville | Linda Morris & Vic Rauseo | September 12, 1990 | 1202.0 |
| 28.0 | 2.0 | "Guess Who's Coming to Doogie's" | Stephen Cragg | Nat Berntein & Mitchel Lee Katlin | September 19, 1990 | 1201.0 |
| 29.0 | 3.0 | "Ask Dr. Doogie" | Win Phelps | Phil Kellard & Tom Moore | September 26, 1990 | 1204.0 |
| 30.0 | 4.0 | "C'est la Vinnie" | Joan Darling | Michael Swerdlick | October 3, 1990 | 1205.0 |
| 31.0 | 5.0 | "Car Wars" | Brad Silberling | Nick Harding | October 10, 1990 | 1207.0 |
| 33.0 | 7.0 | "Academia Nuts" | Ed Sherin | Nick Harding | October 24, 1990 | 1203.0 |
| 34.0 | 8.0 | "Revenge of the Teenage Dead" | Win Phelps | Nat Berntein & Mitchel Lee Katlin | October 31, 1990 | 1209.0 |
| 35.0 | 9.0 | "Nautilus for Naught" | Matia Karrell | Nick Harding & Tara Ison & Neil Landau | November 7, 1990 | 1211.0 |
| 36.0 | 10.0 | "Don't Let the Turkeys Get You Down" | David Carson | Nick Harding | November 14, 1990 | 1214.0 |
| 37.0 | 11.0 | "Oh Very Young" | Joan Darling | Linda Morris & Vic Rauseo | November 28, 1990 | 1210.0 |
| 38.0 | 12.0 | "TV or Not TV" | Joan Tewkesbury | Phil Kellard & Tom Moore | December 5, 1990 | 1212.0 |
| 39.0 | 13.0 | "A Woman Too Far" | Victoria Hochberg | Phil Kellard & Tom Moore | December 12, 1990 | 1206.0 |
| 40.0 | 14.0 | "Presumed Guilty" | Stephen Cragg | Phil Kellard & Tom Moore | January 2, 1991 | 1215.0 |
| 41.0 | 15.0 | "To Live and Die in Brentwood" | Scott Goldstein | Nat Berntein & Mitchel Lee Katlin | January 9, 1991 | 1213.0 |
| 42.0 | 16.0 | "Air Doogie" | Rob Thompson | Nat Berntein & Mitchel Lee Katlin | January 23, 1991 | 1217.0 |
| 43.0 | 17.0 | "A Life in Progress" | Sandy Smolan | Hollis Rich | January 30, 1991 | 1216.0 |
| 44.0 | 18.0 | "My Two Dads" | Bill D'Elia | Nick Harding | February 6, 1991 | 1218.0 |
| 45.0 | 19.0 | "Nobody Expects the Spanish Inquisition" | Stephen Cragg | Nick Harding | February 13, 1991 | 1220.0 |
| 46.0 | 20.0 | "Fatal Distraction" | Gabrielle Beaumont | Phil Kellard & Tom Moore | February 20, 1991 | 1219.0 |
| 47.0 | 21.0 | "The Doctor, the Wife, Her Son and the Job" | Brad Silberling | Hollis Rich | March 13, 1991 | 1221.0 |
| 48.0 | 22.0 | "Planet of the Dateless" | Kristoffer Siegel-Tabori | Nat Berntein & Mitchel Lee Katlin | March 20, 1991 | 1122.0 |
| 49.0 | 23.0 | "Doogie's Wager" | Charles Haid | Hollis Rich | April 3, 1991 | 1224.0 |
Question:
When joan tewkesbury is the director what is the number in seasons?
Answer:
12.0