<OrderBy><FieldRef Name='Modified' /><FieldRef Name='Author' /></OrderBy><Where><Eq><FieldRef Name='Author' /><Value Type='Integer'><UserID /></Value></Eq</Where><QueryOptions><RowLimit>1</RowLimit></QueryOptions>



Or



<View><Query><Where><Eq><FieldRef Name='Author' /><Value Type='Integer'><UserID /></Value></Eq</Where><QueryOptions><RowLimit>1</RowLimit></QueryOptions><OrderBy><FieldRef Name='Modified' /><FieldRef Name='Author' /></OrderBy></Query></View>