What you need to look for are A4-Autotiles with a black center, but due to the limited display size that center will not be visible on the editor selection place.
For example, go to the database in any default project, to the tileset tab and select the "Dungeon" tileset. Then open the picture for the A4 tilesheet.
In the tilesheet, second row, right end, you'll see two walls that have a black center in the full autotile - but are displayed with solid four blocks for the first and an interrupted small stone pattern for the second example in the editor.
Select these walls in a testmap and you'll see how a wall done with them really looks in the game, and use the database to check which tiles produce similiar walls.
However, it might also be that the wall in your example was done with parallax mapping - in that case you won't find that tile anywhere. But you'll be able to find similiar tiles now that you know what to look for.
