Results: Fix results_data delete.

src/Model/Results/Results.py

@@ -193,7 +193,8 @@ class Results(SQLSubModel):
             f"AND solver_type = '{solver_type}'"
         )
         if len(old_pid) != 0:
-            old_pid = old_pid[0]
+            for pid in old_pid:
+                pid = pid[0]
 
                 execute(
                     "DELETE FROM results " +
@@ -203,7 +204,7 @@ class Results(SQLSubModel):
                 execute(
                     "DELETE FROM results_data " +
                     f"WHERE scenario = {self._owner_scenario} " +
-                f"AND results = '{old_pid}'"
+                    f"AND result = {pid}"
                 )
 
     def _db_save(self, execute, data=None):