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:
| Stage | Start | Arrival | Duration | Difficulty |
| --- | --- | --- | --- | --- |
| 1.0 | Maó | Es Grau | 3 h 30 min | Middle |
| 2.0 | Es Grau | Favàritx | 3 h 30 min | Middle |
| 3.0 | Favàritx | Arenal d'en Castell | 5 h | Middle |
| 4.0 | Arenal d'en Castell | Cala Tirant | 4 h | Easy |
| 5.0 | Cala Tirant | Binimel·là | 4 h | Middle |
| 6.0 | Binimel·là | Els Alocs | 5 h | Difficult |
| 7.0 | Els Alocs | Algaiarens | 4 h 30 min | Middle |
| 8.0 | Algaiarens | Cala Morell | 2 h 10 min | Middle |
| 9.0 | Cala Morell | Punta Nati | 3 h | Easy |
| 10.0 | Punta Nati | Ciutadella | 4 h | Easy |
| 11.0 | Ciutadella | Punta d’Artrutx | 5 h | Difficult |
| 12.0 | Punta d'Artrutx | Cala en Turqueta | 5 h | Middle |
| 13.0 | Cala en Turqueta | Cala Galdana | 2 h 30 min | Easy |
| 14.0 | Cala Galdana | Sant Tomàs | 4 h 30 min | Middle |
| 15.0 | Sant Tomàs | Son Bou | 2 h 30 min | Easy |
| 16.0 | Son Bou | Cala en Porter | 3 h 30 min | Middle |
| 17.0 | Cala en Porter | Binisafúller | 4 h 30 min | Easy |
| 18.0 | Binisafúller | Punta Prima | 3 h 30 min | Easy |
| 19.0 | Punta Prima | Cala de Sant Esteve | 2 h 40 min | Easy |
| 20.0 | Cala de Sant Esteve | Maó | 2 h 20 min | Easy |
Question:
How long does the one that stars with son bou of middle difficulty, and on a stage number larger than 13 last?
Answer:
3 h 30 min