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:
| District | Incumbent | Party | First elected | Result | Candidates |
| --- | --- | --- | --- | --- | --- |
| Pennsylvania 6 | Hugh Scott | Republican | 1946.0 | Retired to run for U. S. Senate Democratic gain | Herman Toll (D) 55.4% Fred C. Gartner (R) 44.6% |
| Pennsylvania 9 | Paul B. Dague | Republican | 1946.0 | Re-elected | Paul B. Dague (R) 61.9% James C. N. Paul (D) 38.1% |
| Pennsylvania 12 | Ivor D. Fenton | Republican | 1938.0 | Re-elected | Ivor D. Fenton (R) 54.9% Charles E. Lotz (D) 45.1% |
| Pennsylvania 16 | Walter M. Mumma | Republican | 1950.0 | Re-elected | Walter M. Mumma (R) 56.6% John H. Bream (D) 43.4% |
| Pennsylvania 17 | Alvin Bush | Republican | 1950.0 | Re-elected | Alvin Bush (R) 56.0% C. Max Hess (D) 44.0% |
| Pennsylvania 22 | John P. Saylor | Republican | 1949.0 | Re-elected | John P. Saylor (R) 57.0% Robert S. Glass (D) 43.0% |
Question:
How many incumbents come from alvin bush's district?
Answer:
1.0