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:
| # | Title | Director | Writer(s) | Originalairdate | Repeatairdate(s) | Prod.Code |
| --- | --- | --- | --- | --- | --- | --- |
| 1.0 | "The Magic Shillelah" | Hollingsworth Morse | Frank Crow Leo Rifkin | 15/09/1968 | 16/03/1969, 03/08/1969 | 30-14 |
| 2.0 | "Huck Of La Mancha" | Hollingsworth Morse | George Eckstein | 22/09/1968 | 26/01/1969 | 30-9 |
| 3.0 | "The Terrible Tempered Kahleef" | Bruce Bilson | Joanna Lee | 29/09/1968 | 23/03/1969, 24/08/1969 | 30-7 |
| 4.0 | "The Little People" | Walter S. Burr | (Unknown) | 06/10/1968 | 30/03/1969, 31/08/1969 | 30-3 |
| 5.0 | "Pirate Island" | Byron Haskin | Kenneth L. Kolb | 13/10/1968 | 13/04/1969, 17/08/1969 | 30-4 |
| 6.0 | "The Last Labor of Hercules" | Hollingsworth Morse | David Duncan | 20/10/1968 | 06/04/1969, 08/10/1969 | 30-6 |
| 7.0 | "The Gorgon's Head" | Hollingsworth Morse | Herman Miller | 27/10/1968 | N/A | 30-16 |
| 8.0 | "The Castle Of Evil" | Walter S. Burr | Kenneth L. Kolb | 03/11/1968 | 20/04/1969 | 30-5 |
| 9.0 | "Hunting The Hunter" | Hollingsworth Morse | Kenneth L. Kolb | 24/11/1968 | 27/04/1969 | 30-11 |
| 10.0 | "The Curse Of Thut" | Bruce Bilson | David Duncan | 01/12/1968 | 22/06/1969 | 30-2 |
| 11.0 | "The Ancient Valley" | Hollingsworth Morse | David Duncan | 15/12/1968 | 29/06/1969 | 30-13 |
| 12.0 | "Menace In The Ice" | Walter S. Burr | Peter Allan Fields | 22/12/1968 | 15/06/1969 | 30-10 |
| 13.0 | "The Eye Of Doorgah" | Robert Gist | Herman Miller | 29/12/1968 | 13/07/1969 | 30-1 |
| 14.0 | "Mission Of Captain Mordecai" | Ezra Stone | Joanna Lee | 05/01/1969 | 11/03/1969 | 30-8 |
| 15.0 | "The Jungle Adventure" | Hollingsworth Morse | Bill Lutz | 19/01/1969 | 18/03/1969 | 30-15 |
| 16.0 | "Son Of The Sun" | Hollingsworth Morse | Al C. Ward Kenneth L. Kolb | 26/01/1969 | 06/07/1969 | 30-19 |
| 17.0 | "Prophecy Of Peril" | Hollingsworth Morse | David Duncan | 02/02/1969 | 27/07/1969 | 30-17 |
| 18.0 | "Strange Experiment" | Hollingsworth Morse | Kenneth L. Kolb | 09/02/1969 | 06/07/1969 | 30-12 |
| 19.0 | "The Conquistador Curse" | Bruce Bilson | Tom and Helen August | 16/02/1969 | 01/06/1969 | 30-18 |
Question:
who is the writer of the episode with prod.code 30-17
Answer:
David Duncan