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 |
| --- | --- | --- | --- | --- | --- |
| Ohio 1 | Tom Luken | Democratic | 1976.0 | Re-elected | Tom Luken (D) 56.5% Steve Chabot (R) 43.5% |
| Ohio 2 | Bill Gradison | Republican | 1974.0 | Re-elected | Bill Gradison (R) 72.3% Chuck R. Stidham (D) 27.7% |
| Ohio 3 | Tony P. Hall | Democratic | 1978.0 | Re-elected | Tony P. Hall (D) 76.9% Ron Crutcher (R) 23.1% |
| Ohio 4 | Mike Oxley | Republican | 1972.0 | Re-elected | Mike Oxley (R) Unopposed |
| Ohio 5 | Del Latta | Republican | 1958.0 | Retired Republican hold | Paul Gillmor (R) 60.6% Tom Murray (D) 39.4% |
| Ohio 6 | Bob McEwen | Republican | 1980.0 | Re-elected | Bob McEwen (R) 74.3% Gordon R. Roberts (D) 25.7% |
| Ohio 7 | Mike DeWine | Republican | 1982.0 | Re-elected | Mike DeWine (R) 73.9% Jack Schira (D) 26.1% |
| Ohio 8 | Buz Lukens | Republican | 1986.0 | Re-elected | Buz Lukens (R) 75.9% John W. Griffin (D) 24.1% |
| Ohio 9 | Marcy Kaptur | Democratic | 1982.0 | Re-elected | Marcy Kaptur (D) 81.3% Al Hawkins (R) 18.7% |
| Ohio 12 | John Kasich | Republican | 1982.0 | Re-elected | John Kasich (R) 80.1% Mark P. Brown (D) 19.9% |
| Ohio 13 | Don Pease | Democratic | 1976.0 | Re-elected | Don Pease (D) 69.8% Dwight Brown (R) 30.2% |
| Ohio 14 | Thomas C. Sawyer | Democratic | 1986.0 | Re-elected | Thomas C. Sawyer (D) 74.7% Loretta Lang (R) 25.3% |
| Ohio 16 | Ralph Regula | Republican | 1972.0 | Re-elected | Ralph Regula (R) 78.6% Melvin J. Gravely (D) 21.4% |
| Ohio 19 | Ed Feighan | Democratic | 1982.0 | Re-elected | Ed Feighan (D) 70.5% Noel F. Roberts (R) 29.5% |
| Ohio 20 | Mary Rose Oakar | Democratic | 1976.0 | Re-elected | Mary Rose Oakar (D) 82.6% Michael Sajna (R) 17.4% |
Question:
Who are all the candidates who ran in the district where Ralph Regula is the incumbent?
Answer:
Ralph Regula (R) 78.6% Melvin J. Gravely (D) 21.4%