The normal way of storing lists in a database, is to store the members in a separate table from the table they relate to, and then having a foreign key relationship to join each list entry with table row it relates to. (This is why it is called a relational database.)
The way you have done it with four columns for the four possible array entries will be fine, but if you later discovered that there could be many more entries in the array, you would have to modify that table, and you would waste a lot of space with extra slots that are unused.
On the other hand, the way you have done it will be faster, as it avoids the need to do a database join, and if you are sure there will only ever be four entries in the array, then the small penalty of wasted slots will be small.