Oracle Analytics - partitions and ordering of sql queries

ROW_PRIORITY   COL1     COL2    COL3
0              0.1      100     <NULL>
12             <NULL>   <NULL>  3
24             0.2      <NULL>  <NULL>

select  'B' METRIC, ROW_PRIORITY,
        last_value(col1 ignore nulls) over (ORDER BY ROW_PRIORITY) col1,
        last_value(col2 ignore nulls) over (ORDER BY ROW_PRIORITY) col2,
        last_value(col3 ignore nulls) over (ORDER BY ROW_PRIORITY) col3
from    (SELECT * FROM ZTEST);

METRIC  ROW_PRIORITY	COL1	COL2	COL3
B            0          0.1     100     <NULL>
B           12          0.1     100     3
B           24          0.2     100     3

METRIC  ROW_PRIORITY	COL1	COL2	COL3
B            0          0.2     100     3
B           12          0.2     100     3
B           24          0.2     100     3