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:
| Year | Men's singles | Women's singles | Men's doubles | Women's doubles | Mixed doubles |
| --- | --- | --- | --- | --- | --- |
| 1957.0 | Dave F. McTaggart | Judy Devlin | Don K. Smythe H. "Budd" Porter | Sue Devlin Judy Devlin | Robert B. Williams Ethel Marshall |
| 1958.0 | Dave F. McTaggart | Jean Miller | Don K. Smythe H. "Budd" Porter | Marjorie Shedd Joan Hennessy | William Purcell Marjorie Shedd |
| 1959.0 | Tan Joe Hok | Judy Devlin | Lim Say Hup Teh Kew San | Sue Devlin Judy Devlin | Don P. Davis Judy Devlin |
| 1960.0 | Tan Joe Hok | Marjorie Shedd | Lim Say Hup Teh Kew San | Lois Alston Beulah Armendariz | Finn Kobberø Jean Miller |
| 1961.0 | Erland Kops | Marjorie Shedd | Finn Kobberø Jörgen Hammergaard Hansen | Marjorie Shedd Dorothy Tinline | Finn Kobberø Jean Miller |
Question:
What year did dave f. mctaggart win the men's singles and robert b. williams ethel marshall win the mixed doubles?
Answer:
1957.0