Gardening and Horticulture - Container GArdening Question

I have lots of Pansies left over. I bought two very large containers to plant them in. Then I thought I would plant something bigger in the center and the pansies around it to give it some variety. I thought about planting shasta daisies in the center. The pansies are white with red centers, white with purple centers, purple with deep purple centers and red with deep purple centers.
So what do you think would go good with these? I'm in zone 5 and will put them on the porch. It is shady until about 3-4pm then it get sunlight. I would like something that hopefully will bloom for most of the spring and summer.
Also one last question if they are put in a glassed in porch during the cold months, is it possible that these could last all year long? Sorry just don't know a great deal about flowers but trying to learn.
Thanks for the help

One idea - how about a tall green grassy type plant? I see them all the time in the flower bowls that the garden centers carry - Sometimes it's hard to mix annuals, because they have differing sun and water needs.... Another idea would be to put some small type of evergreen in the center - that way, when the flowers die you still have something in the container, and can surround it with other plants or ivy next season....

Pansies can live to the next year. I have had them in the front bed from year to year. It does not get so hot here to kill them in the summer.

Of course, they seed so there will be sprouts next year. They don't seed true to what you bought, but more dimunitive along the line of Johnny Jump Ups.

Hope this helps.