fixed party not showing in section of speech

src/main/java/org/texttechnologylab/project/gruppe_05_1/database/domainimpl/mdb/Speech_MongoDB_Impl.java

@@ -85,15 +85,16 @@ public class Speech_MongoDB_Impl  extends Speech_File_Impl implements Speech {
     public String toTeX() {
         StringBuilder tex = new StringBuilder();
 
+        String party = (this.getFraction() != null ? " (" + this.getFraction() + ")" : "");
+
         String speechTitle = "Rede " +
                 this.getSpeechKey() +
                 "/" +
                 getAgendaTitle(this.getSessionId(), this.getAgendaItemId()) +
                 " von " +
                 this.getSpeakerName() +
-                " (" +
-                this.getFraction() +
-                ") vom " +
+                party +
+                " vom " +
                 getSessionDateTime(this.getSessionId());
 
         tex.append("\\section*{").append(speechTitle).append("}\n");